Oh No, Not Another LS3/5a... - Hificritic.com

Oh No, Not Another LS3/5a...
THE BBC-LICENSED LS3/5A HELPED MAKE ROGERS INTO A GLOBAL BRAND. ITS CURRENT FAR
EAST OWNERS HAVE WORKED WITH UK DESIGNERS AND MANUFACTURERS TO CREATE THIS
BBC-LICENSED 11OHM ‘REVIVAL’
We won’t labour the LS3/5a story, which
began in the BBC in early 1970s, as
this was covered in depth in Vol1 No3
(May-June 2007). The fit and finish of this ‘official’
£1499/pair Rogers revival was excellent. It certainly
looks the part with its fine matched rosewood veneer,
though the repro Tygan grille material might be
a little softer and more open than the original. As
expected, these speakers use a 5in (138mm) polymer
cone bass/mid drive unit partnered by a nominally
19mm dome tweeter, mounted in a sealed-box
enclosure. Build detail includes thick felt absorption
around the tweeter, to ameliorate reflection effects
from the integral grille frame. (The LS3/5a is meant
to be used with its grille in place.)
This new example has a glued on back, as were
most ‘3/5as. The bass/mid driver has a 110mm
pressed steel chassis with a flared, talc-filled
polypropylene cone, powered by a double-wound
voice-coil (the windings series connected), and a
large ferrite magnet. A fine 19mm tweeter with
recessed soft dome and sophisticated rear loading is
fitted, while that unnecessary perforated metal cover
completes the original look. Built of birch plywood
according to the original recipe, the panels are well
damped by traditional bitumen loaded pads, and the
interior is lined with thick, absorbent polyurethane
foam. This model is bi-wired (unlike the original)
with average quality gold plate brass binding posts
and brass link pins (preferably replaced by copper
wire on installation). The crossover is built on the
usual epoxy glass reinforced PCB, securely bolted
to the panel area around the tweeter. It uses normal
film capacitors, ferrite core inductors, and an array
of resistors forming a calibrated attenuator to achieve
the essential close tolerance matching of mid and
treble levels. (The original 15ohm model used
mu-metal cored transformer inductors and ratio
matching of driver sensitivity levels.)
Sound quality
With references assembled, and memory not too
dimmed from the pleasant experience of that other,
Derek Hughes guided 11ohm ‘3/5a for Stirling
Broadcast (Vol1 No3), I set to. Location as ever, was
free space with little toe-in, and copper links fitted to
the terminals.
From the very start that genuine ‘3/5a magic was
there, though inevitably at modest loudness levels.
Shut your eyes and coloration is really low, and
the soundstage is spacious, deep and focused. The
natural timbre and the elegant, surprisingly deep
image perspective reminds one of much larger and
more costly designs. If a listener doesn’t demand
higher volume levels or need cracking dynamics, it
might not be necessary to go further than this in the
quest for genuine high fidelity.
In my opinion this is the best of the modern ‘3/5a
clones I’ve heard to date. It has quite good coloration
in the low midrange – a weakness of many – though
it is a little ‘boxier’ than the best 15ohm examples. It
is also a little ‘sweet’, not quite as crisp and open as
is possible, though one would not want it as bright
as some later original Rogers 15ohm examples. This
new contender is self-effacing, clean, even, smooth
and well balanced, with a particularly seamless
transition from midrange to treble, albeit a tad
dynamically reticent in the piano’s middle register.
Spacious, transparent and detailed, if a touch ‘darker’
(and therefore not quite a dynamic, expressive,
transparent or ‘powerful’), this new version of that
old trouper just sounds bigger than the original, with
a touch more realism.
This new Rogers certainly has a good percentage
of the better drive and timing of the earliest models.
We should remember that middle period 15ohm
models often sounded hard and ‘forward’ in the
midband, only just meeting the BBC spec. This new
version actually bests a huge number of the less good
15ohm models, never mind the more boring 11ohm
examples and most of the 3/5 ‘clones’ (which were
never proper 3/5as anyway). In reality this Rogers is
MARTIN COLLOMS
HIFICRITIC JULY | AUGUST | SEPTEMBER 2009 43

◆ REVIEW
Amplification was via Orelle
SA100 Evo and Naim
SUPERNAIT, CD replay
from Marantz CD-7, LP from
Linn LP12, Superline/Hi-
Cap, Koetsu RED T, Origin
Live DC supply, cables from
Kimber, vdH, DNM and Yter.
AE Classic 24inch stands on
BluTack ‘peas’.
CONTACT
RoyalHiFi
Tel 01628 820134
e-mail royalhifi@aol.com
Price: £1499/pair
44
quite close to the standard, comparing well with the
equally well mannered and similarly neutral Stirling
Broadcast version. I think that it may be just a little
livelier musically than the Stirling Broadcast, but
reckon you would have to do an A/B to find out.
Measurement
The spec says 83dB/W sensitivity, some 1.5dB
higher than the original 15ohm model, and truthful.
Frequency responses were very tidy, and with superb
pair matching. The on-axis frequency response gives
70Hz to 29kHz +/-3dB, with -6dB points at 60Hz
and 30kHz. Partnering stands should not be too
high because the response dips sharply by 10dB at 10
degrees below the axis in the crossover zone, around
3.3kHz, while remaining perfect at 10 degrees above.
The speaker should therefore be sited at or a little
below seated ear level. The off-axis lateral results were
good too, but that noted dip was beginning to show
itself in the 45 and 60 degree off-axis results. The
small tweeter keeps the output going nicely up to
11kHz off-axis, so it should stay open and clear. The
Rogers Royal LS3/5a Frequency Responses
Rogers Royal LS3/5a impedance (black) and phase
(blue dashed)
bass is understandably limited with some characteristic
‘plumpness’ 80-150Hz, though this is part of the
‘voice’ of this little box. The in-room averaged
response (not shown) is very good: it’s typical for the
size, with good overall power integration and with inroom
bass down to about 50Hz.
The impedance graph shows an average value of
about 7ohms. It’s easy to drive, with a minimum
of 5ohms and moderate variation. The box bass
resonance is seen at 91Hz. The waterfall response is
quite tidy, well integrated in the early response, with
only moderate decay ‘clutter’ thereafter. Enclosure
coloration is low thanks to the good construction
and small acoustic footprint.
Conclusions
This LS3/5a contender can be recommended. It’s
beautifully made with great care and fine finish, and
while I still await the equal of my ancient Robin
Marshall made BBC originals perhaps it simply
cannot be done, as some of the materials used to
make that speaker are no longer available.
Rogers Royal LS3/5a Waterfall decay response
SPECIFICATIONS
Type ______________________________________________
two-way sealed-box
Drivers ______________________________________________
Bass/mid 110mm pressed steel frame, 85mm
______________________________________________
filled polymer cone, twin voice coil
Treble 19mm soft dome, acoustically
______________________________________________
loaded front and back
Crossover ______________________________________________
3kHz
Enclosure 10mm birch multi-ply, real wood
(wxhxd) veneer
Dimensions ______________________________________________
18.8 x 30.2 x 16.8cm
Frequency ______________________________________________
response 70Hz to 20kHz (+,- 3dB)
Impedance ______________________________________________
11 ohms, bi-wire terminals
Sensitivity ______________________________________________
83dB/W
Power ______________________________________________
30-80W
______________________________________________
Price per pair £1500
Contact royalhifi@aol.com
HIFICRITIC JULY | AUGUST | SEPTEMBER 2009